Pumps, motors and other devices which employ a shaft rotatable within or on a bearing often require resilient seals between the shaft and the bearing housing through which the shaft extends. Besides a portion of the rotatable shaft and the bearing itself, the bearing housing contains lubricant to reduce friction within the bearings. Operating conditions may require that the seal between the shaft and the bearing housing inhibit water, air, dirt particles or other foreign objects from contaminating or otherwise deteriorating the lubricant content of the bearing housing. In mechanical seals, the seal between the shaft and the bearing housing usually is provided by two resilient sealing faces in rotatable and sealing relation with one another, one face being stationary relative to the shaft, and the other being in rotational engagement with the shaft.
Given the rotational relationship between the stationary face and the rotary face, a biasing force is usually required to maintain the seal. Various configurations providing for, among other things, biasing force within a mechanical face-type seal assembly are known in the art. For example, U.S. Pat. No. 4,906,008 to Warner describes a seal assembly employing a wave spring, while use of leaf springs and compression springs have also been described, for example, in U.S. Pat. No. 3,799,559 to Kayser and in U.S. Pat. No. 2,844,393 to Jansen, respectively. The use of interconnected canted coils in lip seals has been described in U.S. Pat. No. 4,655,462 to Balsells.
Notwithstanding developments in the prior art, a need continues to exist for a mechanical face-type seal assembly which provides an improved substantially annular biasing force to the sealing faces of a mechanical face-type seal assembly. Prior art configurations provided biasing force at only selected points along the annular surface of the seal faces, often times resulting in uneven wear and increasing the likelihood of leakage at the junction of the sealing faces. As will be further discussed below, so far as is known, cartridge-type configurations have heretofore been unknown in seal assemblies used in bearing housing shaft apertures, especially when relatively thin and/or relatively short assemblies are required. Accordingly, a need also exists for a mechanical face-type seal which has a cartridge-type configuration. Additionally, a need persists for a mechanical face-type seal assembly which can be relatively thin (about 0.15 to about 0.25 inch) in cross-section width, i.e., in a direction transverse to the axis of the shaft, and/or relatively short (about 0.625 to about 0.875 inch) in cross-section length, i.e., in a direction parallel to said axis, and yet has a cartridge-type configuration. As used herein, the term "cartridge" or "cartridge-type configuration" means a configuration of multiple and separate parts which may be installed as a single, preassembled unit.